lkml.org 
[lkml]   [2014]   [Jul]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] ARM: Don't oops when userspace executes kgdb break instructions.
Don't break into kgdb when userspace executes the kernel break instructions
(KGDB_BREAKINST and KGDB_COMPILED_BREAK). The kernel will oops in
kgdb_handle_exception.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
---
The following program will immediately cause a kernel oops:
.globl _start
_start:
udf #65006 @ KGDB_BREAKINST

arch/arm/kernel/kgdb.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c
index 778c2f7..a74b53c 100644
--- a/arch/arm/kernel/kgdb.c
+++ b/arch/arm/kernel/kgdb.c
@@ -160,12 +160,16 @@ static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
static struct undef_hook kgdb_brkpt_hook = {
.instr_mask = 0xffffffff,
.instr_val = KGDB_BREAKINST,
+ .cpsr_mask = MODE_MASK,
+ .cpsr_val = SVC_MODE,
.fn = kgdb_brk_fn
};

static struct undef_hook kgdb_compiled_brkpt_hook = {
.instr_mask = 0xffffffff,
.instr_val = KGDB_COMPILED_BREAK,
+ .cpsr_mask = MODE_MASK,
+ .cpsr_val = SVC_MODE,
.fn = kgdb_compiled_brk_fn
};

--
2.0.1

\
 
 \ /
  Last update: 2014-07-19 01:41    [W:0.039 / U:0.656 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site